Not applicable.
1. Field of the Invention
The present invention relates generally to disk drives, and in particular to an air bearing slider which includes side rail shallow recessed surfaces extending along trailing portions of leading side air bearing surfaces.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes the disk drive base, a cover, at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA).
The spindle motor includes a spindle motor hub that is rotatably attached to the disk drive base. The spindle motor hub has an outer hub flange that supports a lowermost one of the disks. Additional disks may be stacked and separated with annular disk spacers that are disposed about the spindle motor hub. The head stack assembly has an actuator assembly having at least one air bearing slider or head, typically several, for reading and writing data to and from the disk. Each air bearing slider includes a magnetic transducer. An example of a slider is disclosed in U.S. Pat. No. 5,777,825 (incorporated herein by reference) that describes a slider where a center pad disposed at a trailing side contains a transducer. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached sliders are moved relative to tracks disposed upon the disk.
The head stack assembly includes the actuator assembly, at least one head gimbal assembly (HGA), and a flex circuit cable assembly that are attached to the actuator assembly. A conventional xe2x80x9crotaryxe2x80x9d or xe2x80x9cswing-typexe2x80x9d actuator assembly typically comprises an actuator body, a pivot bearing cartridge, a coil portion that extends from one side of the actuator body to interact with one or more permanent magnets to form a voice coil motor, and one or more actuator arms which that extend from an opposite side of the actuator body. The actuator body includes a bore and the pivot bearing cartridge engaged within the bore for allowing the actuator body to rotate between limited positions. At least one head gimbal assembly is distally attached to each of the actuator arms. A head gimbal assembly includes an air bearing slider that is attached to a suspension with a gimbal. The head gimbal assemblies and the flex circuit cable assembly are attached to the actuator assembly. The actuator assembly is controllably rotated so as to move the heads relative to the disks for reading and writing operations with respect to the tracks contained on the disks.
A typical slider design includes leading and trailing sides. A center pad that includes an air bearing surface is disposed adjacent the trailing edge. A transducer is embedded within the center pad. At least one additional air bearing surface disposed upon a pad is provided adjacent the leading side. In this regard, a single air bearing surface may be provided which extends the width of the slider. Alternatively, a pair of air bearing surfaces may be provided at opposite lateral sides of the slider adjacent the leading edge. In addition, a depressed region or cavity is centrally disposed between the center pad and the leading side air bearing surfaces.
A problem that arises with such prior art slider designs is that debris in the form of particulate matter and dense fluids, such as lubricants, may tend to accumulate at the downstream side of the leading side air bearing surfaces. This is because the cavity being downstream of such air bearing surfaces promotes a vacuum effect with air expanding within such region. The accumulated debris negatively impacts the aerodynamic characteristics of the slider because the debris results in a change of the geometry of the slider. In addition, after accumulating, a portion of the debris may become dislodged. In this regard, the accumulation and dislodgement of the debris may be non-symmetrical with respect to the slider further negatively impacting the aerodynamic characteristics of the slider. Moreover, dislodged debris may become attached to the downstream center pad further exasperating the impact to aerodynamic characteristics of the slider. Such changes to the aerodynamic characteristics negatively impact the ability to maintain the slider at the prescribed flying height and introduce instability with regard to pitch and roll control. Accordingly, there is a need in the art for an improved disk drive in comparison to the prior art.
An aspect of the presenting invention can be regarded as the air bearing slider for use in a disk drive. The slider includes a leading side and an opposing trailing side. The slider further includes a pair of leading side air bearing surfaces disposed adjacent the leading side. Each of the leading side air bearing surfaces includes a main portion and a trailing portion extending from the main portion toward the trailing side. The slider further includes a pair of side rails. Each of the side rails is disposed between a respective one of the leading side air bearing surfaces and the trailing side. Each of the side rails includes a side rail air bearing surface disposed toward the trailing side and a side rail shallow recessed surface extending away from the side rail air bearing surface toward the respective main portion and laterally along the respective trailing portion in spaced relation to the respective trailing portion.
According to various embodiments, the side rail shallow recessed surfaces may be disposed laterally between the trailing portions. The trailing portions may be tapered toward trailing side. The side rail shallow recessed surfaces may be tapered toward the leading side. The slider may further include a deep recessed surface disposed between the leading and trailing sides. The deep recessed surface may extend laterally between the side rails. The deep recessed surface may further extend longitudinally between the main portions and the trailing side. The deep recessed surface may further extend laterally between the main portions. The deep recessed surface may further extend between each respective side rail shallow recessed surface and the associated trailing portion. The slider may further include a leading side shallow recessed surface disposed adjacent the leading side and extending between the leading side air bearing surfaces. The slider may further include a trailing side pad including a transducer disposed adjacent the trailing side. The trailing side pad may include a trailing side air bearing surface disposed adjacent the trailing side. The trailing side pad may include a trailing side shallow recessed surface extending towards the leading side from the trailing side air bearing surface.